A so-called digital camera direct print system is becoming common, which directly connects a printer to a digital still camera (hereafter a DSC) via an interface such as a USB and transmits a photographic image stored in a storage medium (memory card) of the DSC to the printer to print it.
In such a print system, a JPEG file of an image to be printed is generally transmitted to the printer from the DSC, and the JPEG file is decompressed, color-converted and resized on the printer side so as to print it by converting it to a printable data format.
As for the DSC, there is a proposed system for processing a photographed image specifically for a print and then transmitting it to the printer to print it.
Japanese Patent Laid-Open No. 8-32911 proposes a digital camera direct print system capable of, by using a unique protocol which is not general, printing an image from the DSC and an image according to a printing aspect such as a paper size on the printer side.
As for Japanese Patent Laid-Open No. 10-290470, an object thereof is to reduce a processing load on a printer, where the JPEG file is decompressed, color-converted and resized by the DSC to convert it to the printable data format so that the converted data is transmitted as printable data to the printer to reduce an image processing load on the printer.
Furthermore, as for Japanese Patent Laid-Open No. 2003-134457, variations in color reproduction characteristics of each printer are corrected on the DSC side to be converted to a general image file such as JPEG and transmitted to the printer. It is thereby possible, according to its description, to obtain a stable image not dependent on printing characteristics of each printer.
The digital camera direct print system is becoming increasingly common because of a communication protocol providing a communication procedure of the above-mentioned digital camera direct print system. Furthermore, there is a remarkable progress as to improvement in image quality of the DSC. Image data sensed and stored by the DSC was 1 million to 2 million pixels per image at the maximum until some years ago. In recent years, however, the DSCs capable of shooting and storing high-resolution images of 8 million or more pixels per image are on sale.
In conjunction with such an increase in the number of pixels of the DSC, the inventors have discovered the following new problems as to the above-mentioned digital camera direct print system.
(1) The number of pixels to be processed on the printer side increases, so that the load on the printer increases.
(2) Size of the image file becomes larger in proportion to the number of pixels so that a transfer load of the image file between the DSC and the printer increases.
Because of these factors, there is a problem arising that print speed is reduced when printing.
It has been newly found out that there are the problems in the case of performing a part of image processing of the image data for printing on the DSC side for the purpose of load sharing of processing, such as the above-referenced well known examples. In any of the well known examples, there is a description to the effect that the printing specification and printing characteristics of the printer are obtained from the printer while there is no concrete description as to a method of communicating information on the printing characteristics of the printer between the printer and the DSC. For instance, in the case of a technique for conveying printing capability of the printer to the DSC in a PictBridge, it is possible for a user, on the DSC side, to arbitrarily set up and select the size and layout on printing on the printer within the capability of the printer. In the case of such a system, however, printing conditions of the printer are not always appropriately set up just by the capability from the printer. As for Japanese Patent Laid-Open No. 8-32911 in particular, the printer notifies the DSC of a currently printable conditions so that the DSC changes the printing conditions accordingly. For instance, it is described that, if A4 paper is set on the printer, the printer having a paper size detecting function automatically notifies the DSC of the paper size of A4. In the case where the printer has no paper size detecting function, the paper size is selected on a panel of the printer so as to notify the selected result thereof to the DSC. In any of the cases, however, only the current printable conditions recognized by the printer is notified to the DSC, but the desired print characteristics of the user on the DSC are not always reflected to the printed matter. For example, consideration is given to the case of having the A4 paper set on the printer and transmitting from the DSC the image data to be printed in a larger size than A4 if printed at a resolution of the printer. In this case, the transmitted image data is too large to be in the size of A4 and is printed in a state of having its periphery chipped.
As for Japanese Patent Laid-Open No. 10-290470 and Japanese Patent Laid-Open No. 2003-134457, there is a description to the effect that the printing characteristics of the printer are obtained from the printer. However, the image data transmitted to the printer is converted based only on the obtained printing characteristics, and so there is no description as to performing the image processing and print processing desired by the user.